Coin detector



Get. 6,1925. 1,555,910

F. R. CHESTER COIN DETECTOR I Filed Nov. 29, 1922 Tiqll.

jiqfl. T1235.

IN V E N TO I? HBHNK f2. Chasm/2 J/mmig Mam M W I ATTORNEY-8 WITNESSES 5 I 19 mm: 1; cmssrmor is emg, nnw" a com nn'rncroa.

A ine-su iied' November 29,1922, Seria1-1l'o.604,047.' f

I To all whom itmdy a citizen of the United sam -and a"re 'sident of Asbury Park, in the county of-Monmouth and State of New Jersey", have'im vented a certain new and Improved Coin Detector, of which the following is a full,

before such coin goes to said apparatus.

It has previously been suggested to employ in electric coin-detecting systems, as

in U. S. patent to Kitsee, No. 790,641, a

primary and a secondary circuit, each circuit having a plurality of coils in series, and these coils arranged so that each coil in one circuit is associated inductively with one coil of the other circuit to provide a pair of what may be termed balancer-transformers. According to the Kitsee patent, it has also been proposed to use one of the transformers as what may be termed a tester transformer, and accordingly to arrange the same adjacent to the coin chute so that the coin inserted in the latter will have a certain inductive effect on the system depending on its metallic mass and the metallic elements making up such mass-which effeet is employed in the Kitsee system to permit or prevent the sounding of a distant signal telephonically, as may be very useful in connection with coin-box telephone stations.

According to the system just described, however, the coin intercepted by the detent in the chute, whether such coin be the prevised one or some other, is not automatically released from the system but must be manually released.

The present invention has as its principal object the provision of a system of the balancer-transformer type, but one in which the prevised coin or any other, or even a slug, will be instrumental in automatically restoring the system immediately following the functioning of the latter as a detector of ,the character of the coin last mentioned,

thus dispensing with the need of any human attendant whatsoever, as is deslrable if not economically necessary in pra t y all coini actuated apparatus, except paystationtelephonesf v a The; bjectlastjmentioned is attained by not only, as. in Kitsee, (a) providing pr1 mary and secondary circuits; (1)) interposing in each circuit two,;.coils in series; (0) arranging such coils so that-each coil in a circuit is one of two inductively reactant coils of one of two pairs of transformers; (d) winding the coils of such two transformers so that when one transformer is adjusted to a predetermined inductive relation, the coin inductively adjacent the other or tester transformer balances or unbalances oppositely flowing potential differences in the secondary circuit; (6) providing a coin chute to guide the coin toward inductive relation to the tester transformer and associating with said chute a coin detent; and (f) providing an electromagnet means or the like for moving said coin detent;but by providing certain new and useful variation of the system, characterized chiefly by the features (g) that said electro-magnet means is interposed in one of the primary and secondary coils, but preferably the latter, and so in series with the coils therein, whereas the same means of Kitsee is in a third circuit, the telephone circuit; and (h) that/said electro-magnet means functions to move the coin detent solely as the result of the balanced or unbalanced condition of the secondary circuit, and hence is. an automatically functioning element of the new system, whereas the same means of Kitsee is totally unaffected by the condition of the secondary circuit and is merely a manually operable adjunct in the Kitsee system.

Thus the coin-controlling system of the present invention does not require any human attendant whatsoever, especially since, as the invention is preferably carried out, the coin detent is in inoperative position in the main coin chute at all times except on the occurrence of a certain contingency, to wit, the insertion of a coin other than the prevised one, whereas according to the Kitsee system the detent device is operative at all times except upon the occurrence of a certain contingency, to wit, the manual closing of a circuit to throw the coin detent to inoperative position.

men

Another object of the present invention is to provide, as is desirable, diver ing coinguiding means beyond the main 0 ute, with the parts, and particularly the detent, so arranged that the detent is really only a detent for one of the two diverging coinguiding means below the chute, wherebyautomatically, if the coin is the prevised one, the detent will either remain immovable, to ass the coin on toward, if desired the usua locked receptacle or the like, and in thecourse of such travel release the turnstile, vending machine, or whatever particular apparatus is associated with the coindetectmg system, or, if the coin is not the prevised one, the detent will be moved .by the electro-magnet means to preclude the coin from passing on toward said apparatus, perha s to return the coin to the patron.

A fhrther object of the invention is 'to provide a system which, unlike the Kitsee system, does not re uire the manual insertron of an extra in uctive device into predetermined adjacency to the transformer other than the tester transformer each time the system is to function. In this connection, still another object of the invention is to adapt the transformer for convenient and prevised adjustment or readjustment at any time, but so as thereafter to function without further attention during employment of the system over a long period of time and for a great plurality of successively deposited coins.

With the foregoing and other objects in view, the invention consists in the features of construction, combinations of elements and arran ements of parts which will be exemplifie in the description hereinafter set forth.

In the accompan ing drawings, wherein is shown an illustrative example of a possible embodiment of the invention as at present preferred.

Fig. 1 is a schematic view of such embodiment;

Fig. 2 is a vertical section through the tester coil set, showing the coin chute and appurtenant parts; and

Fig. 3 is a view similar to Fig. 2, but taken on the line 33 of Fig. 2;

Similar reference characters refer to similar parts throughout the several views.

As heretofore proposed, the system illustrated includes a primary circuit 5 and a secondary circuit 6. The primary circuit includes in series two coils 7 and 8 and the secondary circuit includes in series two coils 9 and 10. The coils 8 and 10 form one of the transformers, which may be termed the standard transformer, by which is meant a transformer establishing an inductive standard by which the coin is to be tested; and the coils 7 and 9 form the other or tester transformer, that is, the one with which is assoassaeie battery 13 is employed as here for such source of current or if the current in any manner delivered is direct, the interrupter may be used to establish a pulsating current 1n the primary circuit and hence permit the coils 7 and 8 to'have varying magnetic fields relative to the coils 9 and 10 as in ordinary transformers. In order thatsuch fields will simultaneously tend to induce oppositely flowing currents in the secondary circuit 6, the coils 9 and 10 are oppositely wound.

Said chute 11 has two diverging continuations as shown and marked 11*,and 11" in Fig. 3. By the term main chute as hereinafter used is meant the chute 11 and its continuation 11", while the chute 11 will be considered an entirely different chute and referred to as the auxiliary chute.

The mainfeatures of the new system-of the present invention are four, although various other novel details will be hereinafter specifically pointed out or obvious.

In the first place, a coin-detent 15 is movably associated with the chute 11 and'just below 0011 7, as by means of fixing same on a pivotally mounted shaft 16 so that the de-- tent is normally in inoperative condition relative to the main chute 11-11". detent is thus normally disposed as by a leaf spring 17 (adjustable if desired by a setscrew) to permit a coin to pass beyond the position where the coin has the maximum inductive effect on coil 7 immediately after the coin has been tested; as it will be seen that whether the coin-detent stays as shown in Fig. 3 or is thrown to the broken line position 15 by means hereinafter described, according to whether or not the coin is the prevised one, the coin will pass either into the chute 11 or the continuation 11 of the main chute 11. It is again expressly emphasized that normally the detent is in in- (1)l1)er1ttlVe position relative to the main chute If the coin deposited by the patron in the chute 11 is the prevised coin, the same may thus descend by way of one of the chutes 11. and 11 to enter a suitable lock-box (not shown), or if some other object, the same may descend by one or the other of such chutes to enter any suitable compartment (also not shown) or he returned to the patron by any suitable outlet. Otherwise stated, the detent 15 never needs a human attendant to manually move the same at any Such It is important that the design of the system be such that with the primary circuit 5 (which here is open normally, that is,-when no coin is in the chute 11) closed, the oppositely wound coils 9 and 10 of the secondary circuit 6 are normally unbalanced, that is, opposing currents induced in these coils by induction from coils 7 and 8 are unequal, and so there is a current flow in the secondary circuit whenever the primary circuit is closed, unless the cointhen in chute 11 is the'prevised coin, in whichcase the coils 9 and 10 are balanced, but due solely to the inductive adjacency of said coin, against any current flow in the secondary circuit.

The means for utilizing such a flow of current in the secondary coil to temporarily throw the detent 15 to the position 15 includes an electro-magnet 18 interposed here in the secondary circuit 6. Such means for controlling the detent, constituting the second of the four main features of novelty above mentioned further includes in the present case, and in order to make the movements of the coin-detent responsive to an exceedingly small current flow between the coils 9 and 10, and so make the new system exceedingly accurate in coin detecting, an arrangement whereby the electro-magnet 18 is not the direct magnetic agent for moving the detent, but instead is really a relay for closing a third but wholly manually unattended circuit 19; this third circuit being normally open and closed only when relay 18 is energized sufficiently to attract its very light armature 20, which armature is a circuit-closing means as illustrated for the circuit 19. In said circuit 19 is interposed an electro-magnet 21 which, when energized from its own special source of current 22, will have sufficient strength to move the detent positively and surely the proper amount in accordance with the design and intended operation of the particular system installed. In the present case, when the electro-magnet 21 is energized, the detent is moved to the position shown at 15 by means of an arm 23 acting as an armature for the electromagnet 21, such arm being offset from the shaft 16 on which the coin-detent is mounted. This results in moving the coin detent against spring 17 from inoperative to operative position relative to the main chute 1111, in the sense that the detent is moved to preclude the coin from entering the continuation chute 11- of the main chute and permit the coin to enter the auxiliary chute 11. The continuation chute 11 may lead to a suitable lock-box (not shown) intended to receive only the prevised coins, and the chute 11 may be provided to return the in- ,serted object to the patron if such object not be the prevised coin.

The third of the more important features of the new system as above specified, is not only the normally open condition of one of the circuits 5 and 6 when. one of such cir-" cuits has interposed therein a relay 18 or any electro-magnet means to actuate a train of means to operate the coin-detent as just indicated, but the use of a normally operative coin-interceptor in the chute 11, as the interceptor indicated at 24, adapted to be moved from its normal illustrated location by the passage of a coin through the chute, thereby temporarily to close the normally open primary circuit 5. According to this arrangement thenew system involves really a plurality of coin-interceptors, each movably associated with the coin guiding means; since the coin-detent 15 is really also a coininterceptor. The interceptor 241 is here a single member pivotally mounted as at 25 and normally urged by spring 26 toward protrusion into the chute; the part thus rotr'uded being so shaped and arranged as illustrated, that is, being elongated lengthwise of the chute, that during an appreciable travel of the coin down the chute such member is moved and held to a osition such that "a contact 27 carried there y temporarily closes the primary circuit at the normally open gap 28. It will be seen from Fig. 2 that during said travel of the coin,

it is moved into maximum inductive relation to the coils 7 and 9 of the tester transformer, and hence will before the coin may pass beyond the interceptor 24 thereby to cause an automatic reopening of the primary circuit, the coin-detent 15 will remain as shown or be moved as the result of elec tric coin detection according to the invention. In the present case, as is preferable, the coin does not release the interceptor 24 to permit the latter to reopen the primary circuit until the coin has safely entered either the chute 11- or 11 according to whether the two transformers are inductively balanced or unbalanced. Thus, i1nmediately after the coin is directed into .its proper chute 11 or 11", the consequent reopening of the primary circuit automatically restores the entire system including an automatic redisposition of the coin-detent 15 to inoperative position (if necessary) in readiness for the approach of another patron.

The fourth of the main important features of the new system as above specified is the arrangement of the system such that the system may be readily set for a coin of any desired denomination, and once set may act as predetermined and without further attention or human attendance for a multiplicity of such coins sporadically inserted in the chute 11. That is to say, once the system is adjusted to the inductive condition required according to the design of the system to render the intended'coin, and only the intended coin, effective to balance the two transformers when the primary circuit 5 is temporarily opened by the intertor 24, the system thereafter automatice cally operates entirely without the interpolation of a human agent. To the end just indicated both coils 9 and of the system are associated with convenient means for varying as desired the induction between coils 7 and 9 and between coils 9 and 10. Such means in the present case includes, as shown best in Fig. 1, a pair of sleeve-like slidable mountings 29 and one carrying each of the coils 9 and 10. Setscrews are provided on these mountings as indicated,to hold the coils 9 and 10 any selected distances from coils 7 and 8, which latter coils are fixed, the first on the chute 11 and the second on a suitable fixed support 31. The operation of properly setting the standard transformer comprising the coils 8 and 10 for a prevised coin is substantially as follows:

' One of the prevised coins is dropped into the chute 11 and automatically detained as indicated in Fig. 2 at 14, as by way of an auxiliary temporary detent, as a suitable pin (not shown) inserted into the chute by way of a hole 32; thus holding the coin in maximum inductive adjacency to the coil 7 and also maintaining the interceptor 24 in position to close the normally open gap 28 in the primary circuit 5. Thereupon, one or both the coils 9 and 10 are moved relative to coils 7 and 8 until the coin-detent 15 moves to inoperative position, that is to the full-line position shown in Fig. 3. The system is now delicately, yet very durably and reliably adjusted for roper operation relative to the prevised com; and the coin 14 in chute 11 may be suitably released from said chute merely by removing the temporary auxiliary detent above mentioned.

Unless deliberately intended to be induction-varying factors in the system, the parts closely adjacent the four coils are, of course, made of fibre, wood, bronze, or some other suitable non-inductive material; and with this explanation and the ones foregoing, the operation of the system in service should be clearly understood.

Inasmuch as many changes could be made in the above construction, and many apparently widely different embodiments of my invention could be made without departing from the scope thereof, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

It will also be understood that the language used in the following claims is in tended to cover all the generic and specific features of the invention herein described and all statements of the invention which, as a matter of language, might be said to fall therebetween.

I claim: 1

1. In an electric coin-detector system, the combination of a primary circuit including in series a first coil and a second coil, a secondary circuit including in series a first coil and a second coil, one of'said circuits being normally open said two first coils being in inductive relation and said two sec ond coils being in inductive relation, the two coils in one of said circuits being in balanced relation in said circuit, a coin chute for guiding a coin into inductive relation to one of the sets of inductively related coils, a coin detent movably associated with the chute, means for moving said detent, actuated when the open circuit is closed, and

,means for temporarily closing said open circuit and actuated by the deposited coin before the latter reaches said detent.

2. In an electric coin-detector system, the combination of a primary circuit including in series a first coil an a second coil, a. secondary circuit including in series a first coil and a second coil, said two first coils being in inductive relation and said two second coils being in inductive relation, the two coils in one of said circuits being in balanced relation in said circuit, a coin chute for guiding a coin into inductive relation to one of the sets of inductively related coils, a coin detent movably associated with the chute, and means for moving said detent, the means last mentioned including electro-magnet means interposed in one of said circuits, the means for moving said detent also including a normally open third circuit adapted to be closed by said electromagnet means, said last-mentioned circuit having interposed therein a second electromagnet means adapted on an encrgization thereof to cause such movement of the detent.

3. In an electric coin-detector system, the combination of a primary circuit including in series a first coil and a second coil, a secondary circuit including in series a first coil and a second coil, said two first coils being in inductive relation and said two second coils being in inductive relation, the two coils in one of said circuits being in balanced relation in said circuit, a coin chute for guiding a coin into inductive relation to one of the sets of inductively related coils and then immediately out of such inductive relation, one of said circuits being normal- 1 v open, and means actuated by the coin in passing through such chute to momentarily close the circuit last mentioned.

4. In an electric coin-detector system,

the combination of a primary circuit in eluding in series a first coil and a second coil, a secondary circuit including in series a first coil and a second coil, said two first coils being in inductive relation and said two second coils being in inductive relah h hut d-mansionim tin asa tion, the two coils in one of said circuits be 'ifidving said second interce tor, and means ing in balanced relation in said circuit, a actuated by apredetermined inductive effect coin chute -i -.;gi 1iding ;a .,co,.i n.1 into,.=inducti;ve;, gon thegsystem' of said coin thereby to operate lll an Eds-01. @fii g stse f;inductiyely:i rme nsatomove said second interceptor.

6 related coils,,onetof,said circuits-being nor-g; 7. In an electric coin-detector system, the mally, 99th,. swit h-means ifl ml dwbvg he eooinbinat-ioir 0t sazprimary circuit including coing during,gpassage,through;a;predeteimr,in seriessa :firsticoil and a second coil, a 11' ne,l ,lengthpfis cltchu e t ia osei th ciis; secondarypcircuitdncludi -in series a first cuit last ment ioned, and means automatic'al coil'; and ca second coil, said two first coils l0 ly restoring the circuit la t; mentioned ,to ;being in; inductive-relation and said two secopen condition aftergthe coingpasses, beyond ondrcoils being-in inductive relation the two said ,swit ch means; l X c0,i15.'=i;1:011e;0f said circuits being in balanced ni la gniin' saidzcircuit, a coin chute for guid- -g- 1 1 ,anle tric .comwdc r. yst m tlrecombination of a primarypircuitinclud ingyaacoilrzintminductive relation to one of 15 ingin series,afirstwilfandgasecond; 5 mm r heisecondary circuit ineludingjnaseries;first detentiniovably-associated with the chute, coil andasec ndcOiI sMd lnvosfirst,( ;:o i ls.=,2g and meanstior moving said detent, the being;in,;inductive1re1ati0nQand ,gsaidttwo uneans las'tiz-mentioned including electrodf l b j i induct, yea e dtion,, th ,magnetr-vmeansl-interposed in the secondary two coils in -one otsaid. irpujt b i f ciriouit,-:oneof said circuits'being normally balanced relation finjsaid, circuit a, icoin openyanddhere being provided a movable s cliute for guiding avcoin.ifli illd ctiyeprela- ;interceptorlforethe coin in the chute and tion ,to one ofthesetsiot,inductively related; presentingwmmielongated surface against coils,,. af coin detent,.,moyabl. associated whit the =coin?};travels in descending the I ,chute, closing means for said open circuit detent lthe' means last,mentipnuiddncluding,E daptedifp betthrown to operative position electro-ni agnet means interposed ,in lg i'lig-straiveliofi 'acoin against such surface, ondaryicircuit, one-fl'of said circuits heir; a .second cl 1ute, =.:a seoond movable interfiT.= .y- T Pen an$1; ithe tbemg pmvid .aiceptorassacmted wlth the two chutes, am1 switch, ,actuated the coin during means tokl'l dvesa'id second interceptor actupassage through,.'the,,chute,,bet vee1 a, first; atedsby lmcll'rrent flow in the secondary cirhigher point andja secgnd lower ,=po i,nt,therecu t resultmg from the inductive adjacency in. to, close 's ai d open c rcuit, a movable coin f; said icoinfizto the system.

- the coiii as the latter approaches-,thkedetentg m series hifimt coil an a second coil, a to m 'v; =;f said. detent when the ixfductixie secondary-circuit including in series a first vsihieQjbiQsfiid coin bears 1a,.;predetermined coil: andia: second coil said two first coils relationftio .the inductive valueQof gthe prem beinguin inductive relation, the two coils vised coin.' Q inonetofr said'circuits being in balanced 6, In'an lectric coine ecto system,-tlie relation--in;said=circuit, a means for guiding I combination, of, ,a primary c'i including, a coinintozinductive relation to one of the in' series aifirst'l'coil and secon lcoil,"a,' sets ofxinductively related coils, and an Sew -daydream including.infseriesja first; electro-magnetu-in series with two of the coil a'nd a'jsecoin d,coilg said two firstfpoilsj coils,a';.movable coin interce tor associated beingin' inductive relation {and said two sec; I- w1th;said:guiding means, an means operat- 0nd coils being in inductive relation, the two. I ed by said electro-magnet to move said intercoilsinoneofsaidcircuits beingdnbalanced ccptor,;-,the, circuit other than the one inrelation circuit,afcoi n chuteiorjguidcludin ;said-,electro-magnet b ein normally ing in c'oin'into' 'induct'ive relation toj one or, ,opem'st rere belngfurther provid means for the 'f's'ets'fof inductivelyirelzitcd' coils, a, oin temporarily. closing such open circuit durde'tentjl 'inov'a'bly associated withjthe cl ute', ing. ;passage of a coin through said guiding arid mef fs j0r;moving saididetent t1 'e. means.-;: 1 mean-stin s mentioned;in ;i 1ing,, 1cu- 9, In amelectric coin-detector system, the magnetfineansjinterposed. inlthe secondary; combination ot-a primary circuit including circuifi' 'one 'ofsaidcircuitsbeinglnormally in-seriesa first coil and a second coil, a openian dthere beipgg1 rovid da 'mOi'aDleQsecOndary, circuit including in series a first int ipto'r 'fo'rl 'the coin; i hechute,andfllcoiliand a second coil, said two first coils "'elon atedlf surface. nagainstf being ing. inductive relation and said two det intfinth ]v,1c1nity oilthedattergpoiiit, an, In! anielectric coin-detector system, the means {controlled fby'the inductiveyalueo combination z-of-ia primary circuit including H lt'ravels i in d'scei dingithej Isecond coils being in inductive relation, the chute; jclosin meansfforlsaidfopen, c rcuitl ztwo coils =in one of said circuits being in adapted to betlirow'n tobpefitivc \positioribalanced relation in said circuit, means for during travel' ofa coin aga nst sub surface guiding-a coininto inductive relation to one a second chrite, a'secondmovablel nterceptor ofthe sets of inductively related coils, thus associated ivith'the two'chute's', means for to disposea coin relative to the system to :ofrzinductively related coils, a coin being in inductive relation and said two second coils being in inductive relation, the two coils in one of said circuits being in balanced relation in said circuit, means for guiding a coin relative to the system to inductively alfect the same, one of said circuits being normally open, a plurality of movable coin interceptors associated with said guiding means at diiferent levels, closing means for such normall open circuit controlled b the position of t e upper interceptor, an normally inoperative means ada ted to move the lower interceptor and rendered operative by the closing of such v normally open circuit.

coils will be 11.. In an electric coin-detector system, the combination of a primary circuit including in series a first coil and a second coil, a secondary circuit including in series a first coil and a second coil, said two first coils being in inductive relation and said two second coils being in inductive relation, the two coils in one of said circuits being in balanced relation in said circuit, means for iding a coin relative to the system to iniictively affect the same, one of said circuits being normally open, means for closing said normally open circuit, means for adjusting the coils whereby said oppositely wound recisely balanced when the prevised coin is in said guiding means and said normally open circuit is closed, adjustable auxiliary guiding means for receiving a coin from the first guiding means, and means, for adjusting .such auxiliary means when such coin fails to balance said oppositely wound coils.

12. In an electric coin detector system, the combination of primary and secondary circuits one normally open and one including a plurality of coils in series, said coils being constituted, wound and spaced so as to tend to set up oppositely flowing currents in said circuit when both coils are inductively affected, and means whereby the introduction of a coin in the system will close said open circuit and inductively affect the same there being also provided means to guide such coin along a predetermined path and means brought into operation by a coin of a ditferent inductive value to guide the latter coin along a different path.

.13. In an electric coin detector system the combination of primary and seconda circuits one normally open and one inclu ing a plurality of coils in series, said coils beingcoustituted, wound and spaced so as to tend to set up oppositely flowing currents in said circuit when both coils are inductively affected, and means whereby the introduction of a coin in the system will close said open circuit and inductively affect the same, there being provided means for automatically reopening the circuit last mentioned after passage of the coin beyond its location of maximum inductive eflect.

14. In an electric coin detector system, the combination of primary and secondarycircuits one normally open and one including a plurality of coils in series,-sai'd coils being constituted, wound and spaced so as to tend to set up oppositely flowing currents in said circuit when both coils are inductively affected, and means whereby the introduction of a coin in the system will close said open circuit and inductively afiect the same,

there being also provided means to guide such coin along a predetermined path and means brought into operation by a coin of a different inductive value to guide the latter coin along a different path, means for reopening the circuit last mentioned, and means for restoring said deflecting means,

the two means last mentioned automatically opcratingafter passage of a coin beyond its location of maximum inductive effect.

15. In an electric coin-detector system, the combination of primary and secondary circuits one normally open and one including a plurality of coils in series, said coils being constituted, wound and spaced so as to .tend to set up oppositely flowing currents in said circuit when both coils are inductively affected, means whereby the introduction of a coin in the system will close said open circuit and inductivel affect the same, said means including relatively movable contacts in said open circuit, and means actuated by the introduction of a coin into the system for moving said contacts relatively to cause them in and by themselves to close said 16. In an electric coin-detector system, the combination of primary and secondary cir cuits one normall open and one including a plurality of coi in series, said coils being constituted, wound and spaced so as to tend to set up oppositely flowing currents in said circuit when both coils are inductively affected, and means whereby the introduction of a coin in the system will closesaid open circuit and inductively affect the same, said system includuing a coin interceptor movable from an eflective to an ineffective position, and vice versa, said means includmg a switch thrown and held to a certain setting by and during movement of a coin in the system, said switch while thus thrown and held closing said open circuit.

17. In an electric coin-detector system, the combination of primary and secondary circuits one normally open and one including a plurality of coils in series, said coils being constituted, wound and spaced so as to tend to set up oppositely flowing currents in said circuit when both coils are inductively aflected, and means whereby the introduction of a coin in the system will close said open circuit and inductively aifect the same, said system including a coin interceptor movable from an effective to an ineffectlve position, and vice versa, sald means including a switch actuated by the coin folditional to said interceptor.

FRANK R. CHESTER. 

